Problems with JSON API tests in Play2

code.scala

object BetaInvitationRequestController extends Controller {
  val successResponse = Map("success" -> true)

  val betaInvitationRequestMapping = Forms.mapping(
    "email" -> Forms.email
  )(BetaInvitationRequest.apply)(BetaInvitationRequest.unapply)

  val betaInvitationRequestForm = Form(betaInvitationRequestMapping)

  def create = Action {
    implicit request => {

      betaInvitationRequestForm.bindFromRequest.fold(
        formWithErrors => BadRequest(formWithErrors.errorsAsJson),
        value => Ok(Json.toJson(successResponse)
        ))
    }
  }
}

specs.scala

running(FakeApplication()) {
//        val json = Json.parse("""{"email":"mike@example.com"}""")
//        val json = "{\"email\":\"mike@example.com\"}"
        val json = """{"email":"mike@example.com"}"""
//        val request = FakeRequest(POST, "/betaInvitationRequest", FakeHeaders(), json)
        val request = FakeRequest(POST, "/betaInvitationRequest", FakeHeaders(), json).withHeaders(CONTENT_TYPE -> "application/json")
        val createInvite = route(request).get

        "returns a 200 response" in {
          status(createInvite) must equalTo(OK)
        }

        "returns a success response in JSON format" in {
          contentType(createInvite) must beSome.which(_ == "application/json")
          contentAsString(createInvite) must beEqualTo("{\"success\":true}")
        }

        "creates a betaInvite record" in {
          pending
        }
      }

When I run the above code via curl, it works as expected. When I run the tests I get the following results:

when the submitted email is valid

'400' is not equal to '200'
Expected :200
Actual :400

java.lang.Exception: '400' is not equal to '200'
at test.api.BetaInvitationRequestSpec$$anonfun$1$$anonfun$apply$mcV$sp$1$$anonfun$apply$5$$anonfun$apply$6.apply(BetaInvitationRequestSpec.scala:26)
at test.api.BetaInvitationRequestSpec$$anonfun$1$$anonfun$apply$mcV$sp$1$$anonfun$apply$5$$anonfun$apply$6.apply(BetaInvitationRequestSpec.scala:26)

returns a 200 response

'{"email":["error.required"]}' is not equal to '{"success":true}'
Expected :{"success":true}
Actual :{"email":["error.required"]}

java.lang.Exception: '{"email":["error.required"]}' is not equal to '{"success":true}'
at test.api.BetaInvitationRequestSpec$$anonfun$1$$anonfun$apply$mcV$sp$1$$anonfun$apply$5$$anonfun$apply$8.apply(BetaInvitationRequestSpec.scala:31)
at test.api.BetaInvitationRequestSpec$$anonfun$1$$anonfun$apply$mcV$sp$1$$anonfun$apply$5$$anonfun$apply$8.apply(BetaInvitationRequestSpec.scala:29)

It looks to me like the JSON isn't getting submitted properly.